Copyright Prairie Grains Magazine
February 2001

New Field Guide Provides Pieces to Grain Production Puzzle

By Dr. Jochum Wiersma, University of Minnesota small grains specialist,
wiers002@tc.umn.edu

The University of Minnesota and the Minnesota Wheat Research and Promotion Council have partnered to produce “The Minnesota Small Grains Production Field Guide.” The Minnesota Wheat Checkoff sponsored the development of 10,000 copies of this book, to be distributed to grain growers throughout Minnesota and made available online, at www.smallgrains.org... to be distributed to grain growers throughout Minnesota and soon will made available online.

Nearly 200 pages with about 90 color photos, this pocket-sized, spiral bound book contains 7 sections: Agronomic Management, Fertility Management, Weed Management, Disease and Pest Management, Harvest and Storage Management, Marketing, and Photographs. It is intended as a quick reference and field guide for managing virtually all facets of wheat, barley, and oat production.

As stressed in the introduction of the guide, successfully growing wheat, barley, or oats can be very complex. Variety selection, proper fertilization, good weed control, and the ability to identify and eliminate yield robbing diseases and pests are all pieces of the puzzle. Each piece requires attention to solve the whole puzzle profitably. 

Following are some excerpts from the Guide:

Key crop rotation questions
Important questions to consider when designing a crop rotation, regardless of location are:  How will the previous crop affect subsequent crop production? Will the previous crop increase or decrease concerns in the following areas? Rotation studies in Fargo over a nine-year period showed a 40, 20, and 15 % increase in grain yield when wheat followed soybean, sunflowers, or flax, respectively, as compared to continuous wheat.

Mix and match varieties
Different weather and/or occurrence of a disease can change the performance of a variety, and ranking of the variety, relative to other varieties in close proximity for an individual grower. The best defense against this is to mix and match a number of varieties rather than use a single variety for all the fields on the farm.  This hedging approach can be best compared to spreading risk by investing in a mutual fund rather than a single stock. By selecting two or three varieties instead of one you hedge against the potential that one of the varieties falters due to a negative environmental interaction.

Determining a yield goal
Setting a realistic yield goal is important when developing a production plan and cash flow. The most often used method to determine a yield goal is based on historic production data of a particular field. Methods to set a realistic yield goal:

• 5-year average of the farm

• 5-year average plus 5%

• 5-year average plus 10 bushels

• Set yield goals such that it is equal to highest yield in past five years

There are additional considerations to fine-tune a yield goal. First, variety selection influences your yield goal, especially if you changed varieties. None of the methods mentioned above address this, but you could calculate a factor based on the relative difference in performance of the varieties to adjust for the yield potential of the variety. Secondly, when using the average of the farm, adjust the yield goal upwards or downwards if experience has told you that the particular field in question has performed better or worse than the other fields.

Adjust the yield goal upwards if you made significant improvements to a field, such as improved drainage, or if you have adopted management practices that improved yields dramatically in the past few years. Should planting be delayed due to adverse conditions, the yield goal should be adjusted downward accordingly.

Minimum, Optimum, and Maximum Growth Temperatures for Small Grains   Growth Temperature   Crop Mimimun, oF Optimum, o F Maximum, o F Wheat 37-39 75-77 86-90 Barley 37-39 68-70 82-86 Oat 37-39 68-70 82-86 From “The Minnesota Small Grains Production Field Guide,” a project of the University of Minnesota and the Minnesota Wheat Research and Promotion Council, funded by the Minnesota Wheat Checkoff.

Fertilizer applied with air seeders
The use of air seeders has increased in popularity in recent years.  Many seeders are equipped to apply a mixture of seed and dry fertilizer at the time of planting. There are, however, no firm guidelines for the amount of fertilizer that can be applied with the seed when this planting equipment is used.

The amount of urea (46-0-0) that can be used with the air seeder is related to soil moisture content at planting.  Recent trials showed that N rates in excess of 25 lb per acre can reduce germination if applied with the wheat in an air seeder when soils are dry.  By contrast, 75 lb N per acre as 46-0-0 caused no emergence problems when soils were wet.

Recent trials have shown that phosphate rates of 92 lb P2O5 per acre supplied as 18-46-0 have not hindered germination if mixed with wheat seed planted with an air seeder.  The amount of K2O that can be applied in contact with the seed using an air seeder is not known at this time.

Trials have not been conducted to evaluate the application of fertilizer with barley or oat in an air seeder, but recommendations that pertain to fertilizer use for spring wheat production also apply for these crops.

Reducing weed control costs
There are many possibilities for reducing weed control costs while still attaining good weed control. Wise selection of weed control practices and herbicides to fit specific field situations is the key. Identify your weeds and develop an effective, low cost control program that is suitable for the crop you plan to grow. Reducing herbicide rates below those recommended increases the possibility of costly weed control failure. On the other hand, applying herbicides at greater than recommended rates adds unnecessarily to your weed control costs and may result in crop injury or herbicide carryover.

Applying herbicides at the proper time and rate with a carefully calibrated applicator provides the best return on your herbicide investment. Sowing clean seed at an adequate seeding rate will help to reduce weed population in small grains.  Also, small grains must be seeded early so the cool season small grain crop can compete effectively with weeds. Early spring seeding reduces warm season annual grass weed problems such as foxtail (pigeongrass). However, early spring seeding does not help to reduce wild oat populations.

Perennial weeds, such as quackgrass, should be controlled prior to seeding small grains (preferably the year before). Most herbicides available for use in small grains will control many annual weeds, but will not adequately control established perennial weeds.

Seedling diseases, seed treatments
Shriveled, low test weight, diseased, or weathered seed may benefit from seed treatment through protection against seed-borne or soil-borne fungi.  Cold, wet soils slow the growth of seedlings, and favor growth of certain disease organisms. Seed treatment stops these organisms from causing decay and rot. Different fungicides may be used for different purposes. Select the correct fungicide for the job.  Some seed treatment formulations are a combination of fungicide and insecticide.  Always avoid over-application with seed treatment products and apply a fungicide to seed that has been well cleaned and germinates above 85%.

Sampling insect pests in small grains
Although there are a number of insect pests in wheat, not all of them are problems every year. An exception, perhaps, are aphids and Orange Wheat Blossom Midge (OWBM), and both should be scouted every year. Other occasional common insect pests in wheat include grasshoppers, thrips, wheat stem maggot, common stalk borer, wheat stem sawfly, and wireworms. Correct identification of insect pests is important for scouting efforts to be successful.  Given that over 99% of all animals are insects, it is easy to understand that many insect species may appear similar but are not equal threats to crops.  A good example of this are Lauxanid flies in wheat. They are a similar color to Orange Wheat Blossom Midge, are found within the wheat field in large numbers but are not damaging to the crop.

Grain harvest
Grain loss at harvest is a direct loss of income. Harvesting often is a compromise between getting the job done in a reasonable period of time and living with a reasonable seed loss.  Studies have shown that losses can run as high as 20%, even with a properly adjusted machine when it is overloaded.  A reasonable loss is considered to be 3% of the total crop or less.  Total harvest losses are seldom if ever zero.  Usually over 60% of the grain left in the field is due to shattering of the crop and grain lost in getting it cut and into the combine header.  Once the crop is in the combine, loss is very low with properly adjusted and operated equipment.

Managing stored grain
Every two to four weeks in cold weather and every one to two weeks in warm weather, measure grain temperature and moisture, and look for moldy, discolored, or crusted kernels, and for signs of insects. Permanently installed cables that hold electronic temperature sensors can make checking grain temperature much easier. Also, start the fan briefly and smell the first air to leave the bin for musty or sour odors. If problems are detected, run aeration fans to cool the grain. If aeration doesn’t control the problem, unload the bin and clean, dry, feed, or sell the grain. Wear a dust mask designed to filter mold spores when you handle moldy grain to avoid health problems caused by mold spores.

Molds and insects need moisture to live and reproduce, so make sure grain is dry before it is stored. Maximum recommended moisture content for wheat is 14% (wet basis) for up to 9 months storage, and 13% for more than 9 months storage.  Barley moisture should be 13.5% and 12.5%, respectively, for the same storage periods. In late fall or early winter, use aeration fans to cool grain to 20 to 30 °F for winter storage. Cooling grain limits mold and insect activity and it reduces moisture migration. If grain is not stored at less than 20 °F during winter, you shouldn’t need to run fans to warm the grain in spring. If you do run fans in spring, start early in the season (March or April) and make sure you don’t warm grain beyond 50 °F. More information from the U of M on post-harvest crop handling can be found online: www.bae.umn.edu/extens/postharvest.